Liquid control for gas wells



June 13, 1967 K. KELLEY ETAL LIQUID CONTROL FOR GAS WELLS Filed April27, 1965 United States Patent() 3,324,803 LIQUID CONTRGL FOR GAS WELLSKork Kelley, 518 W. 7th, and Robert K. Kelley, Box 892, both of Liberal,Kans. 67901 Filed Apr. 27, 1965, Ser. No. 451,187 9 Claims. (Cl. 10S-232) This invention relates to improvements in a liquid control for gaswells and more particularly to devices for limiting and removingaccumulations of liquids which would otherwise interfere with gasproduction.

Liquids such as water and/or oil, etc. tend to accumulate in manyproducing gas wells. It is necessary to remove these liquids,particularly the water, because the lillling up of the bore holerestricts the flow of the gas. If ynot removed, the water level willrise or build up in the bore hole and in time will kill the well or'stop the iiow of gas completely.

Various methods are presently Ibeing utilized to remove accumulations ofwater from gas wells. ln some instances, it is pumped out by theconventional rod-type pump driven by a pumping unit at this surface. Inother wells, a small tubing string is installed from the surface downinto the well bore, and the gas pressure in the well is used to ow thewater -out through the tubing string. The flow provided in this mannercan 'be either constant or intermitten. However, constant flow isextremely wasteful because, once the water is exhausted from the well,the gas under pressure contained therein is vented `directly to theatmosphere.

Known systems for providing intermittent ow through the tubing stringare controlled either manually or by cycle timer devices. Manual controlis costly because it requires almost constant attendance at each well inorder to open the valve in the tubing string when a certain quantity ofwater accumulates and to close the valve as soon as the accumulation ofwater is exhausted from the well. Cycle timers are ineicient, costly,and require fairly constant attendance. If the valve in the tubingstring is left open for too short a period, not all of the Water will beexhausted from the well during each cycle and a water -buildup willoccur. lf the valve is left open for too long a period, all of thewaterwill be exhausted and very considerable quantities of gas will beallowed to escape.

In quite deep or comparatively low pressure wells, the stored energycontained in-the compressed gas is not Sullicient to lift the column ofliquid contained in the tubing "string 'and the described modes ofoperation are impossible. ln such cases, devices known las gas liftshave been employed to inject gas from 'the well bore into the tubing-string in such manner as to lift relatively short columns or slugs ofliquid through the tubing string to the surface. However, the foregoingcomments relating to manual and cycle timer intermittent liow controlapply equally to these gas lift devices.

The present invention contemplates an apparatus for automaticallycontrolling the removing of the accumulation of liquids from gas well bylifting slugs of liquid through the tubing string only so long as liquidis available at the entrance thereto. This is accomplished by mountingan automatic, bucket-type liquid-gas separator at the lower end of thetubing string in such manner as to coact with a gas lift device ordevices to produce the desired results. The tubing string is open to thewell bore ICC only when liquid is available, and the gas lift device isresponsive to the static head of the liquid rising in the tubing stringto inject the compressed gas from the well bore into the tubing 'stringbeneath a column or slug of liquid of the desired height, the gas liftdevice being formed to shut off the flow of gas from the well bore tothe tubing string in response to a pressure drop therein which occurs assoon as the liquid slug is'discharged at the surface.

Accordingly, it is a principal object of the present invention toprovide an apparatus for automatically controlling the removing of theaccumulation of liquids from wells providing a substantial gas pressurein the well bore.

Another object of the present invention is to provide an apparatus ofthe character described which will automatically slug out a portion ofthe liquid as it accumulates to a certain level within the well bore.

A further object of the invention is to provide an apparatus of thecharacter described which will function automatically and in anel'ricient manner to avoid wastage and loss of gas and pressure from theWell.

A still further `object of the present invention is to provide apparatusfor intermittently ejecting accumulations of liquid lfrom -a well fborethrough a tubing string and which functions automatically in response toa predetermined static head within the tubing string.

Yet another object of the present invention is to provide an apparatusof the character described which incorporates a positive actionliquid-gas sepa-rator functioning automatically to Ipermit entry ofliquid from the well bore into the tubing string and to close offcommunication between the tubing string and the well -bore when theliquid supply is exhausted.

Another object of the present invention is to provide an apparatus ofthe character described which is compact, sturdy, foolproof, andmaintenance-free so as to provide a long yoperating life at the bottomo-f a well.

Further objects and advantages of the invention will be apparent as thespeciiication progresses, and the new and useful features of the liquidcontrol for gas wells will fbe fully defined in the claims attachedhereto.

The preferred for-m of the invention is shown in the accompanyingdrawing forming a part of this description, in which:

FIGURE 1 is a vertical cross-sectional View of an apparatus constructedin accordance with the pre'sent invention and mounted within a gas well,portions being broken away and shown in section for clarity ofillustration;

FIGURE 2, `an enlarged vertical cross-sectional view taken substantiallyon the plane of line 2 2 of FIGURE l; and FIGURE 3, an enlarged verticalcross-sectional view of .a gas lift device comprising part of theapparatus of the present invention and shown in operative position withrespect to associated portions of a well bore and tubing string.

While only the preferred form of the invention is shown, it should beunderstood that various changes or modifications may be made within thescope of the claims attached hereto without departing from the spirit ofthe invention.

Referring to the drawings in detail, it will be seen that the apparatusfor automatically controlling liquid depth in gas wells and oil wells ofthe present invention consists essentially of a liquid-gas separator 11operatively positioned within a well bore 12, a tubing string 13 withinthe well bore 12 connected to the liquid-gas separator 11 to receiveliquid accumulations 14 therefrom, and communicating with the surface16, together with a -gas lift device 17 connected to the tubing string13 `and responsive to a predetermined pressure therein for supplying gasunder pressure from the well bore to the tubing string so as to lift acolumn of liquid 18 through the tubing string to the surface.

In accordance with the present invention, the liquidgas separator 11 isof the positive Iaction type which will supply liquid to the tubingstring so long as liquid is present at the entrance thereof, and whichwill automatically closs olf the liquid entrance to the tubing stringwhen the liquid supply thereat is exhausted. Liquid-gas separators ofthis type are disclosed in our Patent No. 2,291,902, issued Aug. 4,1942, and entitled Gas Anchor, and in our copending application Ser. No.433,909, led Feb. 19,

1966, and entitled Method and Apparatus for Eiecting Gas Control in OilWells.

The 'liquid-gas separator 11 includes a valve means 19 adapted forcommunicating the tubing string 13 with the lower portion of theinterior of an open top cylindrical bucket 21 mounted for verticalreciprocaton within the well bore 12. The bucket 21 has a weightsutiicient to pull the valve means 19 open against the gas pressure inthe well when the bucket is partially lled with liquid and also has aneffect-ive displacement sulcient to float the bucket in the surroundingliquid when the bucket is substantially empty, for urging the valvemeans 19 closed.

As here shown, the :liquid-gas separator 11 has its valve means 19 andbucket 21 operatively carried within a capsule 22 secured to the lowerend of the tubing string 13. Openings 23 are forced in the capsule 22 topermit entry of liquid and gas from the well bore 12, .and a bull plug24 is provided at the lower end of the capsule 22 for cleaning out anydebris which may accumulate.

The valve means 19 is here shown as being mounted on the lower end of atube 26 secured in coaxial relation within the capsule 22 and connectedto the tubing string 13 to form an operative extension thereof. Valvemeans 19 here includes a ball check 27 formed to permit liquid to enterthe tubing str-ing but to prevent liquid from leaving the tubing stringthrough the valve means. Also included in valve means 19 is a valvemember 28 connected "by a rod 29 to the bottom of bucket 21 for verticalmovement therewith toward and away from a valve seat 31.

A quantity of liquid is contained within the capsule 22 at all times,this quantity being suicient to cause the bucket, when empty, to oatupwardly and seat valve member 28. When the. liquid accumulation in thewell bore 12 rises to the lowermost of the openings 23, it 'will pourinto the capsule 22 and into the bucket 21. As the lbucket lls, theotation elect is destroyed and the Weight of the bucket is sufficient topull the valve member 28 downwardly away from seat 31 against thepressure in the well bore. The liquid contained within bucket 21 is thenfree to enter the tubing string 13. As the supply of liquid in thebucket 21 is depleted, the flotation effect again overcomes the Weightof the bucket and urges the valve member 28 upwardly to closed position.Thus, it will be seen that the liquid gas separator functionsautomatically to supply liquid to the tubing string 13 as soon as theliquid accumulation in the well bore reaches a predetermined level asdetermined by the openings 23. The liquid gas separator also functionsautomatically to close ol communication between the tubing string 13 andthe well bore 12 .as soon as the supply of liquid in the bucket 21 isexhausted to a predetermined level.

In accordance with the present invention, the gas lift device 17 isformed to respond to a predetermined static head of liquid in the tubingstring 13 above the liquid gas separator 11 to supply gas under pressurefrom the well bore 12 to the tubing string a spaced distance below theliquid level therein so as to lift a column or slug 18 of 4 liquidthrough the tubing string 13 for discharge therefrom at the surface 16.

Preferably, the gas lift device 17 includes a Valve formed forcommunicating the well bore 12 with the iuterior of tubing string 13,means tending to hold the valve in closed position with a predeterminedforce, and pressure responsive means in the gas lift device formed forovercoming the last-named means and urging the valve to open position inresponse to va predetermined pressure in the tubing string.

As here shown the gas lift device 17 includes a housing 32 providing areference chamber 33 filled with a predetermined qu-antity of gas toprovide a predetermined pressure. A bellows 34 is connected to thereference chamber 33 and to a valve member 36 which is movablevertically toward and away from a valve seat 37 upon expansion andcontraction of the bellows.

The bellows 34 hermetically separ-ates the chamber 33 from a valvechamber 38 provided by housing 32 and in which valve member 36 and valveseat 37 are contained. Chamber 38 is in communication with the interiorof tubing string 13. Bellows 34 has an effective actuating area exposedto the pressure in chamber 38 which is larger than the effectiveactuating area of the valve member 36, as defined by the area of thevalve seat 37 which communicates through ball check valve 39 with theinterior of the well bore 12.

The reference pressure contained within -chamber 33 is related to theeffective actuating area of bellows 34, the eifective actuating area ofvalve member 36, and the gas pressure in the well bore |12 in suchmanner that the valve 36 is urged downwardly to closed position untilsuiicient pressure exists in tubing string 18 to 'join with the upwardforce exerted on valve member 36 by the gas pressure in the well bore toovercome the downward force exerted by the reference pressure incih-amber 33 and cause the valve 36 to move upwardly away from seat 37.

Thus, it may be seen that the static head of liquid entering the tubingstring through the liquid-gas separator 11 will eventually exertsufficient pressure in chamber 38 to trigger the gas lift device andsnap the valve open, admitting gas under pressure from the well boreinto the tubing string. This gas under pres-sure will continue to flowinto the tubing string lifting the slug of liquid ahead of it until theslug reaches the surface and is discharged. It should be noted that thepressure in chamber 38, when valve 36 is closed, is determined by thestatic head of the liquid contained in the tubing string. Accordingly,the reference pressure contained in chamber 33, taken in connection withthe geometry of the bellows 34 and valve and seat 36 and 37 willdetermine the height the liquid will reach in the tubing string at whichthe described triggering open of the lgas lift device will occur.

In particularly deep wells, it may be necessary to install additionalgas lift devices in yorder to life the slug of liquid through the tubingstring to the surface. Each of these gas lift devices can be of astructure substantially the same as the gas lift device described andfunction in a similar manner. Accordingly, detailed description of thestructure and function of the additional gas lift devices should not benecessary.

When the slug of liquid reaches the surface and is discharged into theyopen air, as from pipe 41, the back pressure caused by the weight ofthe liquid slug will be removed and the pressure in reference chamber 33will act through bellows 34 to cause the valve 36 to snap downwardlyagainst seat 37. The gas lift device 17 will remain in its closedoperative position until such time as sufficient liquid accumulates inthe well to pass through the gasliquid separator 11 and rise in thetubing string 13 to the desired height, whereupon the static head yofthe liquid will again trigger the gas lift device 17.

From the foregoing it will be seen that the liquid control for gas Wellsof the present invention operates in a highly ecient manner to ejectunwanted accumulations of liquid from gas producing wells in anintermittent manner, utilizing the gas pressure within the well andbeing responsive 'to accumulati-ons of liquid within the well above adesired level.

We claim:

1. An apparatus for controlilng liquid depth in gas wells and oil wells,comprising a positive action liquidgas separator operatively positionedWithin the well bore, a tubing string within the well bore connected tosaid liquid-gas separator to receive liquid therefrom and communicatingwith the surface, and a gas lift valve connected to -said tubing stringand responsive to a predetermined pressure therein for supplying gasunder pressure from the well bore to said tubing string so as to lift acolumn lof liquid through the tubing string to the surface.

2. An apparatus for automatically controlling liquid depth in gas wellsand oil wells, comprising a liquid-gas separator supported in operativeposition within the Well bore and having valve means controlled byemptying and lling of a bucket for allowing passage therethrough of aliquid While preventing passage of a gas, a tubing string within thewell bore connected to the valve means of said liquid gas separator toreceive liquid therefrom and communicating with the surface, and a gaslift valve positioned Within the well bore and connected to said tubingstring for supplying gas under pressure from the well bore, said gaslift valve being formed to respond to a predetermined static head ofliquid in said tubing string above said liquid-gas separator wherebywhen the liquid level in said tubing string reaches a predeterminedheight said gas lift valve will open to supply gas under pressure fromthe well bore to the tubing string a spaced distance below said liquidlevel so as to lift a column of liquid through the tubing string fordischarge therefrom at the surface, said gas lift valve being responsiveto the pressure drop in the tubing string occurring upon discharge ofsaid column of liquid therefrom to shut ot the supply of gas underpressure from the Well bore to said tubing string.

3. An apparatus for controlling liquid depth in gas wells and oil wells,comprising a positive action liquidgas separator operatively positionedwithin the Well bore, a tubing string within the well bore connected tosaid liquid-gas separator to receive liquid therefrom and communicatingwith the surface, and a gas lift valve positioned above said liquid-gasseparator and connected to said tubing string thereat, said gas liftvalve being formed for supplying gas under pressure from the well boreto said tubing string fin response to a predetermined static head in thetubing string for lifting a column of liquid through the tubing stringfor discharge therefrom outside of the well bore.

4. An apparatus for controlling liquid depth in gas Wells and oil wells,comprising a positive action liquid-gas separator operatively positionedwithin the well bore, a tubing string within the well bore connected tosaid liquid-gas separator to receive liquid therefrom and communicatingwith the surface, and a gas lift valve connected to said tubing stringand responsive to a predetermined pressure therein for supplying gasunder pressure from the Well bore to said tubing string so as to lift acolumn of liquid through the tubing string to the surface; said liquidgas separator Ibeing attached to the lower end of said tubing string ata desired location within the well and including an open topped bucketformed for vertical reciprocation within the well bore, and valve meanscommunicating said tubing string with the lower portion of the interiorof said bucket, said bucket being connected to said valve means andhaving a weight sutlicient to pull said valve means open against the gaspressure in the well when said bucket is partially filled with liquidand having an effective displacement suliicient to float said bucket inthe surrounding liquid when said bucket is substantially empty forurging said valve means closed.

5. An apparatus as described in claim 4, land wherein said valve meansis mounted in the lower portion of the interior of said bucket andincludes a valve member movable vertically toward and away from a valveseat connected to the intake end of the tubing string, and a check valveproviding one-Way flow into the tubing string.

6. An apparatus for controlling liquid depth in gas Wells and oil wells,comprising a positive action liquid-gas separator operatively positionedwithin the well bore, a tubing string within the well bore connected tosaid liquid-gas separator to receive liquid therefrom and communicatingwith the surface, and a gas lift device connected to said tubing stringand responsive to a predetermined pressure therein for supplying gasunder pressure from the well bore to said tubing string so as to lift acolumn of liquid through the tubing string to the surface; said gas liftdevice including a valve formed for communicating the interior of thewell bore with the interior of said tubing string, means in said gaslift device tending to hold said valve in closed position with apredetermined force, and pressure responsive means in said gas liftdevice formed for overcoming said last-named means and urging the valveto open position in response to a predetermined pressure in said tubingstring.

7. An apparatus as described in claim 6, and wherein said gas liftdevice provides a reference chamber lilled with a predetermined quantityof gas to provide a predetermined presure, a bellows connected to saidreference chamber and said valve and formed to provide an eiectiveactuating area larger than the effective actuating area of said valvewhereby the pressure in said reference chamber acting through saidbellows will hold said valve in closed position against gas pressure insaid Well bore until the pressure within said tubing string reaches apredetermined amount.

8. im apparatus for controlling liquid depth in gas wells and oil wells,comprising a positive action liquidgas separator operatively positionedwithin the Well bore, a tubing string within the well bore Connected tosaid liquid-gas separator to receive liquid therefrom and communicatingwith the surface, and a gas lift device connected to said tubing stringand responsive to a predetermined pressure therein for supplying gasunder pressure from the well bore to said tubing string so as to lift acolumn of liquid through the tubing string to the surface; said liquidgas separator being attached to the lower end of said tubing string at adesired location within the well and including an open topped bucketformed for vertical reciprocation within the well bore, and valve meanscommuncating said tubing string with the lower portion of the interiorof said bucket, said bucket having a weight sutiicient to pull saidvalve means open against the gas pressure in the Well when said bucketis partially filled with liquid and having an effective displacementsuliicient to oat said bucket in the surrounding liquid when said bucketis substantially empty for urging said valve means closed; said gas liftdevice including a valve formed for communicating the interior of thewell bore with the interior of said tubing string, means in said gaslift device tending to hold said valve in closed position with apredetermined force, and pressure responsive means in said gas liftdevice formed for overcoming said last-named means and urging the valveto open position in response to a predetermined pressure in said tubingstring.

9. An apparatus as described in claim 8, and wherein said valve means ismounted in the lower portion of the interior of said bucket and includesa valve member movable vertically toward and away from a valve seatconnected t-o the intake end of the tubing string, and a check valveproviding one-way flow into the tubing string, and wherein said gas liftdevice provides a reference chamber filled with a predetermined quantityof gas to provide a predetermined pressure, a bellows connected to saidreference chamber and said valve and formed to provide an effectiveactuating area larger than the effective actuating area of said valvewhereby the pressure in said reference chamber acting through saidbellows will hold said valve in closed position against gas pressure insaid well bore until the pressure Within said tubing string reaches apredetermined amount.

V8 References Cited UNITED STATES PATENTS 2,128,475 8/1938 Rodger-s1.03--40 ROBERT M. WALKER, Primm Examiner.

MARK NEWMAN, DONLEY I. STOCKIN G,

Examiners.

W. J. KRAUSS, Assistant Examiner,

1. AN APPARATUS FOR CONTROLLING LIQUID DEPTH IN GAS WELLS AND OIL WELLS,COMPRISING A POSITIVE ACTION LIQUIDGAS SEPARATOR OPERATIVELY POSITIONEDWITHIN THE WELL BORE, A TUBING STRING WITHIN THE WELL BORE CONNECTED TOSAID LIQUID-GAS SEPARATOR TO RECEIVE LIQUID THEREFROM AND COMMUNICATINGWITH THE SURFACE, AND A GAS LIFT VALVE CONNECTED TO SAID TUBING STRINGAND RESPONSIVE TO A PREDETERMINED PRESSURE THEREIN FOR SUPPLYING GASUNDER PRESSURE FROM THE WELL BORE TO SAID TUBING STRING SO AS TO LIFT ACOLUMN OF LIQUID THROUGH THE TUBING STRING TO THE SURFACE.